Conventionally, surface-modifying treatment of modifying each surface of various materials such as metal and resin plates and pipe materials has been performed for a purpose of providing functions such as waterproofness, corrosion resistance, heat resistance, an insulation property, abrasion resistance, lubricity, adhesion, decorativeness and beauty. There is a case where such surface modification is performed on an inner surface of a tube. In this case, methods for modifying an inner surface of a tube include, for example, a technique of coating an inner surface of a tube made of metal or resin with a resin film having predetermined functions (see, for example, Patent Literatures 1 and 2), and a technique of causing particles having predetermined functions to adhere to an inner surface of a tube made of metal or resin (see, for example, Patent Literatures 3 and 4).